~/.nix-defexpr, otherwise the attribute cannot be selected with the
`-A' option. Useful if you want to stick a Nix expression directly
in ~/.nix-defexpr.
computing the store path (NIX-77). This is an important security
property in multi-user Nix stores.
Note that this changes the store paths of derivations (since the
derivation aterms are added using addTextToStore), but not most
outputs (unless they use builtins.toFile).
containing functions that operate on the Nix store. One
implementation is LocalStore, which operates on the Nix store
directly. The next step, to enable secure multi-user Nix, is to
create a different implementation RemoteStore that talks to a
privileged daemon process that uses LocalStore to perform the actual
operations.
concatenation and string coercion. This was a big mess (see
e.g. NIX-67). Contexts are now folded into strings, so that they
don't cause evaluation errors when they're not expected. The
semantics of paths has been clarified (see nixexpr-ast.def).
toString() and coerceToString() have been merged.
Semantic change: paths are now copied to the store when they're in a
concatenation (and in most other situations - that's the
formalisation of the meaning of a path). So
"foo " + ./bla
evaluates to "foo /nix/store/hash...-bla", not "foo
/path/to/current-dir/bla". This prevents accidental impurities, and
is more consistent with the treatment of derivation outputs, e.g.,
`"foo " + bla' where `bla' is a derivation. (Here `bla' would be
replaced by the output path of `bla'.)
This simplifies garbage collection and `nix-store --query
--requisites' since we no longer need to treat derivations
specially.
* Better maintaining of the invariants, e.g., setReferences() can only
be called on a valid/substitutable path.
promise :-) This allows derivations to specify on *what* output
paths of input derivations they are dependent. This helps to
prevent unnecessary downloads. For instance, a build might be
dependent on the `devel' and `lib' outputs of some library
component, but not the `docs' output.
`derivations.cc', etc.
* Store the SHA-256 content hash of store paths in the database after
they have been built/added. This is so that we can check whether
the store has been messed with (a la `rpm --verify').
* When registering path validity, verify that the closure property
holds.
